Cement thickness and microleakage under metal-ceramic restorations with a facial butted margin: an in vivo investigation.

Ten metal-ceramic restorations with buccal porcelain butt margins and palatal metal beveled margins were fabricated for periodontally hopeless teeth. After cementation, the experimental crowns remained in the oral environment for 3 to 6 months; the teeth were then extracted and used for microscopic and microleakage evaluation. All ten crowns showed at least a small amount of microleakage, but adaptation of beveled margins proved to be superior to that of shoulder porcelain margins.